Oscillation detector



R BRowNLiE oscILLATIoN DETEcToR Filed Jan. 19, 1924 fl? Z Patented Apr.21,19z5, i i i 1,534,769

UNITED kSTATES PATENT OFFICE.

ROLAND BROWNLIE, OF MEDFORD, MASSACHUSETTS.

OSCILLATION DETECTOR.

Application led January 19, 1924i.v Serial No. 687,203.

To all fav/2,0m t may concern.' use in a reflex system which may be very Be it known that I, ROLAND BnowNLm, simply adjusted both as to the point of coricitizen of the United States, and a resident tact between the crystal and the small-areaed of Medford, in the county of Middlesex and member, and as to the presure of said State of Massachusetts, have invented a new Contact.V

and useful Improvement inl Oscillation Dey IVith the foregoing objects in view my intectors, of which the following 1s a speciir veqn'tion comprises means such as a cam for cat-lon. effecting the longitudinal movement of the My invention' relates to voscillation detec- Small-areaed contact member awayfrom the tors of the crystal type and more especially crystal upon a slight rotational movement to such detectors adapted for use in reflex of the member to which it is secured, one radio telephone receiving systems. arrangement whereby this result may be ef- In reflex radio telephone receiving systems i fected consisting of a pin projecting laterin which the high frequency current after ally flOm a lOtatable inger-piece or head amplification is rectified by a myst-1.1 and the rigidly secured to the stud which carries the resulting low frequency current again passed Contact member, said pin taking into any through the vacuum tubes for amplification On@ 0f 2L Series Of indentations in the outer of the same, it is highly desirable to employ face Of a flanged bearing in which fsaid stud a crystal detector which does not require 1s iournalled. much attention on the part of the operator A practicable embodiment of my invenand which will remain at one adjusted posi` tion is shown in the drawings which accom.- tion for a considerable period without loss pany and form a part of this specificationin sensitiveness, so as to leave the operator Figure l is a central longitudinal section free to manipulate the several tube and cirouf a crystal detector embodying my inven- 25 cuit controls. In crystal detectors of the tion; 75

prior art, a change in the point of contact Fig. 2 is an end view of the same, and between the small-areaed contact member Fig. 3 is a transverse section taken on the and the crystal may involve the scratching line 83 of Fig. l. of the face of the crystal by moving said In the drawings selected for more fully contact member over the face of the same disclosing my invention 10 is a tubular cas- 80 from one position to anothernand although ing ofrinsulation material in one end of this may be avoided by raising'the contactwhich is threaded the cap 11 which conmember from the crystal before moving the stitutes a support for the crystal 12 preferformer to a new point on the surface of the ably embedded in a capsule of easily fusible y latter, it is not generally known that the metal 13. Threaded in the other end of said S5 dragging of the contact member across the tubular casing is the flanged bearing 14 for face of the crystal will impair its sensitvethe rotatable stud 15 which carries the conness, and generally a new point vof contact tact member 16, said contact member being is obtained by slightly rotating or otherwise shown in the present instance as the end of moving the contact member support without a spiral 17 enclosed in a bore in the end of 90 irst drawing the same away from the` said stud. Interposed between the inner end crystal. of the bearing 14 and the collar 18, which It is therefore the principalobject of the vpreferably is integral .with the stud, is a present invention to provide means 'for au-V spiral spring 1 9 for maintaining the contact tomatically breaking the contact between the member in co-operation with the face of the small-areaed member and the crystal when crystal. the point of contact between these elements Preferably the Contact member is aris varied. l ranged as shown eccentrically to the'longi- Other objects of my invention are to protudinal axis of the crystal so .that after the y A "9 vide acrystal detector especially adapted for stud is adjusted axially, the end of the wire 100 may be brought into contact with any one ot' a series of points radially displaced 'trom the center of the exposed tace of the crystal.

A convenient means for adj usting the stud axially consists of the head 2() of insulation material rigidly connected with said stud, and in the present instance shown as having threaded engagement therewith. A pin 21 having a knurled head 22 is threaded into said head and the inner end thereof projects laterally therefrom and takes into any one of a series of indentations 28, herein shown as eight in number, `formed in the outer tace of the flanged bearing let, the said pin per forming two functions, viz, lirst it serves to vary the tension of the spring 19 and thereby the pressure ot the Contact; member on the crystal, and, second, it makes it impossible to rotate the stud or adjust the same axially without breaking the contact between the small-areaed member 16 and the crystal.

In ettect, the pin 21 and its co-operating indentations 23 constitute a cam and camfollower, for the indentations are shallow, their depth being approximately equal to onehalf the diameter ot the pin, and as the head is rotated, the end ot the pin will ride over the indented surface formed in the outer face ot the flanged bearing 14 and thereby move the stud longitudinally away from the crystal a distance equal approximately to the depth of the indentation, and then after an eighth otl a turn, in the present instance, the end ot the pin will -fall into the next adjacent indentation` and the end ot' the contact member will rest against the crystal at a. point 450 away from that at which it previously rested, the proper pressure of contact being obtained by a slight adjustment of the head 22.

It will be observed that the eight indentations and the pin 21, co-operating therewith, constitute means for limiting the point ot Contact between the contact: member and the crystal to any one of eight points radially displaced from the center ot the exposed tace of the crystal, it being understood et' course that eight indentations are shown in the present instance merely for the purpose ot illustration.

It will be obvious that after all the points of the crystal displaced a certain radial distance from the center have been used, other series ot points may be obtained by varying the eccentricity ot the Contact member 16 with respect to the axis of the crystal.

In order to prevent the possibility of screwing the pin 21 out of the holD with which it has threaded engagement or turning it sutliciently to bring the end of the pin within said hole or flush with the inner face oit the head, and then rotating saidhead vwithout automatically breaking the contact between the small-areaed member and the crystal, and thereby scratching the surface otl the crystal sutliciently to impair or destroy its sensitiveness, provide a second pin 24 shown in the present instance as arranged diametrically opposite the pin 21, but not adjustable with respect to the head, the said pin being shown in the present instance as screwed into said head and projecting laterally therefrom.

Obviously the pin 24 co-operating with the apertures 23 will constitute a species ot cam in the manner above described in connection with the pin 21.

A convenient means for mounting my improved detector consists as shown in the brackets 25 through apertures near the tops of which the members 11 and 14 pass, and which are interposed between said members and the enclosing tubular casing. The brackets 25 are shown in the present instance as secured to the insulation base 26 by the binding-posts 27.

Having thus described an illustrative embodiment of my invention, without however limiting` the same thereto, what I claim and desire to secure by Letters Patent is:

1. An oscillation detector comprising in combination a crystal, a. supporttor the same, acontact member (3o-operating with said crystal, a support for said contact member, and means automatically breaking the Contact between said member and said crystal when the point of contact between said member and said crystal is varied.

2. An oscillation detector comprising` in combination a crystal, a support for the same, a. contact member co-operating with said crystal, a` rotatable stud carrying said contact member, a learing for said stud, two relatively movable almttiiig members, means securing said stud to one of said members and a cam effecting the longitudinal movement of said stud away Itrom said crystal upon a slight rotational movement ot one ot said abutting members.

3. An oscillation detector comprising in combination a crystal, a support `t'or the same, a contact member co-operating with said crystal, a rotatable stud carrying said Contact member, a flanged bearing for said stud, a head secured to said stud and having its inner tace abutting the outer face ot said flanged bearing, a series of indentations in the outer face of said flanged bearing, a pin projecting laterally from said head and taking into any one of said indentations, and resilient means maintaining said pin in engagement with the outer face ot said flanged bearing.

Ll. An oscillation detector comprising in combination a crystal, a support for the same, a contact member co-operating with said crystal, a rotatable stud carrying said contact member, a flanged bearing for said stud, a head secured to said studI and hav- W ing its inner face abutting the outer face ofsaid flanged bearing, a series of indentations in the outer face of said flanged bearing, an adjustable pin projecting laterally from said head and takingV into any one of said indentations, and resilient means maintaining said pin in engagement with' the outer face of said flanged bearing, the tension of said resilient means being varied by the adjustment of said pin.

In testimony whereof, I have hereunto subscribed my name this 16th day of January, 1924.

ROLAND BROVNLIE. 

